Endoscopy is a medical field which allows the acquisition of images of internal features of a human body, without the need for invasive surgery. A basic tool of endoscopy is an endoscopic camera system, which includes a scope or shaft that is inserted into the body of a patient. Some endoscopic procedures involve the use of a flexible shaft such as, for instance, in the field of gastroenterology. Other procedures involve the use of a rigid shaft such as, for instance, in the field of arthroscopy, thorascopy or laparoscopy. The shaft is normally connected to a camera head that includes electronics for acquiring the image data through the shaft.
The connected shaft and camera head may be held and manipulated during endoscopic surgery by a user (e.g. a surgeon) or by a holding tool, such as a robotic positioning system. The shaft has optical properties which allows it to introduce light into the body of the patient and to transmit light from the body cavity to the camera head. A high intensity light source may be coupled to the shaft by a fiber optic cable to introduce light into the body. The camera head is coupled through a flexible transmission line to a camera control unit, which is often mounted on a mobile cart. The control unit processes video data provided by the camera head to generate images, which are displayed on a video monitor. The control unit may also be coupled to various peripheral devices, such as a printer and a video cassette recorder.
During endoscopic surgery, the surgeon sometimes requires a more close-up view of a feature inside the body. One way of accomplishing this is for the person or machine holding the scope to physically move the scope closer to the feature of interest. This approach has several disadvantages. For example, physically moving the scope consumes valuable time during the surgery while the scope is repositioned. The repositioning process may involve several trial and error steps as the surgeon makes corrections in response to verbal feedback from the surgeon. It may be difficult for a human holder to maintain the scope in precisely the desired position, particularly when fatigue sets in. Furthermore, moving the scope closer to the object of interest might interfere with the surgeon's ability to operate and could potentially heat the object of interest causing damage or trauma to the object of interest.
Some endoscopic camera systems provide the capability to zoom in on an object without having to move the scope closer to the object. However, with such zooming capability, adjusting the configuration of the optics within the scope and/or its connections to the camera head is required. This may be done manually or electronically by pressing a button or other appropriate control. However, these systems require time to adjust and are subject to a certain amount of trial-and-error in zooming. Furthermore, zooming might cause the surgeon to undesirably loose view of the general field of surgery within the body. Reacquiring the more general view requires reverting the zoom lens to a lower magnification setting. Accordingly, it is desirable to have an endoscopic system that overcomes these and other disadvantages of the current endoscopic systems, yet provides the required flexibility and versatility to meet today's endoscopic demands and needs to perform clinical macroscopy and microscopy. For example, other disadvantages of current endoscopic systems could be characterized as: (a) a requirement of a translucent medium (e.g. gas or liquid) in order to visualize the object of interest, (b) limited visibility of the object of interest due to a small range of magnification mostly in the range of 10× to 20×, or (c) imprecise and awkward manipulation due to various cables and connectors in case of a tethered endoscope.